Debugging

Applications can make use of the extensive GStreamer debugging system
to debug pipeline problems. Elements will write output to this system
to log what they're doing. It's not used for error reporting, but it
is very useful for tracking what an element is doing exactly, which
can come in handy when debugging application issues (such as failing
seeks, out-of-sync media, etc.).

Most GStreamer-based applications accept the commandline option
--gst-debug=LIST and related family members. The
list consists of a comma-separated list of category/level pairs,
which can set the debugging level for a specific debugging category.
For example, --gst-debug=oggdemux:5 would turn
on debugging for the Ogg demuxer element. You can use wildcards as
well. A debugging level of 0 will turn off all debugging, and a level
of 9 will turn on all debugging. Intermediate values only turn on
some debugging (based on message severity; 2, for example, will only
display errors and warnings). Here's a list of all available options:

--gst-debug-help will print available debug
categories and exit.

--gst-debug-level=LEVEL
will set the default debug level (which can range from 0 (no
output) to 9 (everything)).

--gst-debug=LIST
takes a comma-separated list of category_name:level pairs to
set specific levels for the individual categories. Example:
GST_AUTOPLUG:5,avidemux:3. Alternatively, you
can also set the GST_DEBUG environment
variable, which has the same effect.

--gst-debug-no-color will disable color debugging.
You can also set the GST_DEBUG_NO_COLOR environment variable to 1
if you want to disable colored debug output permanently. Note that
if you are disabling color purely to avoid messing up your pager
output, try using less -R.

--gst-debug-color-mode=MODE
will change debug log coloring mode. MODE
can be one of the following: on,
off, auto,
disable, unix.
You can also set the GST_DEBUG_COLOR_MODE environment variable
if you want to change colored debug output permanently. Note that
if you are disabling color purely to avoid messing up your pager
output, try using less -R.